Indenotriphenylene-based iridium complexes for organic electroluminescence device

ABSTRACT

The present invention discloses an indenotriphenylene-based iridium complexes is represented by the following formula (1), the organic EL device employing the derivative as light emitting dopant of emitting layer can display good performance like as lower driving voltage and power consumption, increasing efficiency and half-life time. 
     
       
         
         
             
             
         
       
     
     wherein A ring represents an imidazole, a pyridine, a quinoline and an isoquinoline, X 1 -X 2  represents a bidentate ligand, and m, n and R 1  to R 4  are the same definition as described in the present invention.

FIELD OF INVENTION

The present invention generally relates to a indeno triphenylene-basediridium complexes and organic electroluminescence (herein referred to asorganic EL) device using the iridium complexes. More specifically, thepresent invention relates to the indenotriphenylene-based iridiumcomplexes having general formula (1), an organic EL device employing theiridium complexes as light emitting dopant of emitting layer.

BACKGROUND OF THE INVENTION

Organic electroluminescence (organic EL) is a light-emitting diode (LED)in which the emissive layer is a film made by organic compounds whichemits light in response to an electric current. The emissive layer oforganic compound is sandwiched between two electrodes. Organic EL isapplied in flat panel displays due to their high illumination, lowweight, ultra-thin profile, self-illumination without back light, lowpower consumption, wide viewing angle, high contrast, simple fabricationmethods and rapid response time.

The first observation of electroluminescence in organic materials werein the early 1950s by Andre Bernanose and co-workers at theNancy-University in France. Martin Pope and his co-workers at New YorkUniversity first observed direct current (DC) electroluminescence on asingle pure crystal of anthracene and on anthracene crystals doped withtetracene under vacuum in 1963.

The first diode device was reported by Ching W. Tang and Steven VanSlyke at Eastman Kodak in 1987. The device used a two-layer structurewith separate hole transporting and electron transporting layersresulted in reduction in operating voltage and improvement of theefficiency, that led to the current era of organic EL research anddevice production.

Typically organic EL device is composed of layers of organic materialssituated between two electrodes, which include a hole transporting layer(HTL), an emitting layer (EML), an electron transporting layer (ETL).The basic mechanism of organic EL involves the injection of the carrier,transport, recombination of carriers and exciton formed to emit light.When an external voltage is applied to an organic EL device, electronsand holes are injected from a cathode and an anode, respectively,electrons will be injected from a cathode into a LUMO (lowest unoccupiedmolecular orbital) and holes will be injected from an anode into a HOMO(highest occupied molecular orbital). When the electrons recombine withholes in the emitting layer, excitons are formed and then emit light.When luminescent molecules absorb energy to achieve an excited state, anexciton may either be in a singlet state or a triplet state depending onhow the spins of the electron and hole have been combined. 75% of theexcitons form by recombination of electrons and holes to achieve atriplet excited state. Decay from triplet states is spin forbidden,Thus, a fluorescence electroluminescent device has only 25% internalquantum efficiency. In contrast to fluorescence electroluminescentdevice, phosphorescent organic EL device make use of spin-orbitinteractions to facilitate intersystem crossing between singlet andtriplet states, thus obtaining emission from both singlet and tripletstates and the internal quantum efficiency of electroluminescent devicesfrom 25% to 100%. The spin-orbit interactions is finished by some heavyatom such as iridium, rhodium, platinum, palladium and thephosphorescent transition may be observed from an excited MLCT (metal toligand charge transfer) state of organic metallic complexes.

The organic EL utilizes both triplet and singlet excitons. Cause oflonger lifetime and the diffusion length of triplet excitons compared tothose of singlet excitons, the phosphorescent organic EL generally needan additional hole blocking layer (HBL) between the emitting layer (EML)and the electron transporting layer (ETL) or electron blocking layer(EBL) between the emitting layer (EML) and the hole transporting layer(HTL). The purpose of the use of HBL or EBL is to confine therecombination of injected holes and electrons and the relaxation ofcreated excitons within the EML, hence the device's efficiency can beimproved. To meet such roles, the hole blocking materials or electronblocking materials must have HOMO (highest occupied molecular orbital)and LUMO (lowest unoccupied molecular orbital) energy levels suitable toblock hole or electron transport from the EML to the ETL or the HTL.

For full-colored flat panel displays in AMOLED or OLED lighting panelthe material used for the phosphorescent dopant for emitting layer arestill unsatisfactory in half-lifetime, efficiency and driving voltage.These organic metallic complexes still have disadvantages for industrialpractice use.

In the present invention, for the purpose to prolong the half-life timeand lower driving voltage for phosphorescent dopant in emitting layerfor organic EL device, we employ an indenotriphenylene skeleton link toiridium metal, then chelate with one or two bidentate ligand to finishthe metallic complexes represented as general formula (1). The iridiumcomplexes show good thermal stability and charge carrier mobility fororganic EL device. Some prior-arts of iridium complexes such as U.S.Pat. No. 8,795,850B2, U.S. Pat. No. 8,778,508B2, U.S. Pat. No.8,722,205B2, U.S. Pat. No. 8,709,615B2. U.S. Pat. No. 8,779,176B2. Butthere are no prior arts demonstrate an indenotriphenylene skeleton linkto iridium complexes used as light emitting dopant of emitting layer fororganic EL device.

SUMMARY OF THE INVENTION

According to the reasons described above, the present invention has theobjective of resolving such problems of the prior-art and offering alight emitting device which is excellent in its thermal stability, highluminance efficiency, high luminance and long half-life time. Thepresent invention disclose a novel indenotriphenylene-based iridiumcomplexes having general formula (1), used as a light emitting dopant ofemitting layer have good charge carrier mobility and excellentoperational durability can lower driving voltage and power consumption,increasing efficiency and half-life time of organic EL.

The present invention has the economic advantages for industrialpractice. Accordingly, the present invention discloses theindenotriphenylene-based iridium complexes which can be used for organicEL device is disclosed. The mentioned the indenotriphenylene-basediridium complexes is represented by the following formula (1):

wherein A ring represents an imidazole, a pyridine, a quinoline and anisoquinoline, X₁-X₂ represents a bidentate ligand, m represents aninteger of 0 to 2, n represents an integer of 0 to 8, R₁ to R₄ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 show one example of organic EL device in the present invention,wherein 6 is transparent electrode, 14 is metal electrode, 7 is holeinjection layer which is deposited onto 6, 8 is hole transport layerwhich is deposited onto 7, 9 is electron blocking layer which isdeposited onto 8, 10 is fluorescent or phosphorescent emitting layerwhich is deposited onto 9, 11 is hole blocking layer which is depositedonto 10, 12 is electron transport layer which is deposited on to 11, and13 is electron injection layer which is deposited on to 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

What probed into the invention is the indenotriphenylene-based iridiumcomplexes for organic EL device using the iridium complexes. Detaileddescriptions of the production, structure and elements will be providedin the following to make the invention thoroughly understood. Obviously,the application of the invention is not confined to specific detailsfamiliar to those who are skilled in the art. On the other hand, thecommon elements and procedures that are known to everyone are notdescribed in details to avoid unnecessary limits of the invention. Somepreferred embodiments of the present invention will now be described ingreater detail in the following. However, it should be recognized thatthe present invention can be practiced in a wide range of otherembodiments besides those explicitly described, that is, this inventioncan also be applied extensively to other embodiments, and the scope ofthe present invention is expressly not limited except as specified inthe accompanying claims

In a first embodiment of the present invention, theindenotriphenylene-based iridium complexes which can be used as lightemitting dopant of emitting layer for organic EL device are disclosed.The mentioned the indenotriphenylene-based iridium complexes representedby the following formula (1):

wherein A ring represents an imidazole, a pyridine, a quinoline and anisoquinoline, X₁-X₂ represents a bidentate ligand, m represents aninteger of 0 to 2, n represents an integer of 0 to 8, R₁ to R₄ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.

According to the above-mentioned the indenotriphenylene-based iridiumcomplexes formula (1), wherein X₁-X₂ represents the following formulas:

wherein X is a divalent bridge selected from the atom or groupconsisting from O, S, C(R₈)₂, N(R₉) and Si(R₁₀)₂, R₅ to R₁₀ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.

According to the above-mentioned the indenotriphenylene-based iridiumcomplexes formula (1) represented by the following formula (2) toformula (31):

wherein X₁-X₂ represents a bidentate ligand, m represents an integer of0 to 2, n represents an integer of 0 to 8, R₁ to R₄ are independentlyselected from the group consisting of a hydrogen atom, a halide, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms anda substituted or unsubstituted heteroaryl group having 3 to 30 carbonatoms.

According to the above-mentioned the indenotriphenylene-based iridiumcomplexes formula (2) to formula (31), wherein X₁-X₂ represents thefollowing formulas:

wherein X is a divalent bridge selected from the atom or groupconsisting from O, S, C(R₈)₂, N(R₉) and Si(R₁₀)₂, R₅ to R₁₀ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.

In this embodiment, some indenotriphenylene-based iridium complexes areshown below:

Detailed preparation for the indenotriphenylene-based iridium complexespresent invention could be clarified by exemplary embodiments, but thepresent invention is not limited to exemplary embodiments. EXAMPLE 1 andEXAMPLE 4 show the preparation for examples of the derivative in thepresent invention. EXAMPLE 5 shows the fabrication of organic EL deviceand I-V-B, half-life time of organic EL device testing report.

Example 1 Synthesis of EX2 Synthesis of2-(biphenyl-2-yl)-6-bromo-9,9-dimethyl-9H-fluorene

A mixture of 35.2 g (100 mmol) of 3,6-dibromo-9,9-dimethyl-9H-fluorene,21.8 g (110 mmol) of biphenyl-2-ylboronic acid, 2.31 g (2 mmol) ofPd(PPh₃)₄, 75 ml of 2M Na₂CO₃, 150 ml of EtOH and 300 ml toluene wasdegassed and placed under nitrogen, and then heated at 100° C. for 12 h.After finishing the reaction, the mixture was allowed to cool to roomtemperature. The organic layer was extracted with ethyl acetate andwater, dried with anhydrous magnesium sulfate, the solvent was removedand the residue was purified by column chromatography on silica to giveproduct (26.8 g, 63.0 mmol, 63%) as a white solid.

Synthesis of 13-bromo-10,10-dimethyl-10H-indeno[2,1-b] triphenylene

In a 3000 ml three-necked flask that had been degassed and filled withnitrogen, 26.8 g (60 mmol) of2-(biphenyl-2-yl)-7-bromo-9,9-Dimethyl-9H-fluorene was dissolved inanhydrous dichloromethane (1500 ml), 97.5 g (600 mmol) iron (III)chloride was then added, and the mixture was stirred one hour. Methanol500 ml were added to the mixture and the organic layer was separated andthe solvent removed in vacuo. The residue was purified by columnchromatography on silica (hexane-dichloromethane) afforded a white solid(10.7 g, 25.3 mmol, 40%). 1H NMR (CDCl₃, 500 MHz): chemical shift (ppm)8.93 (s, 1H), 8.77˜8.71 (m, 2H), 8.67˜8.65 (m, 3H), 8.08 (d, J=1.5 Hz,1H), 7.71˜7.64 (m, 4H), 7.49 (dd, J₁=8.5 Hz, J₂=1.5 Hz, 1H), 7.37 (d,J=8.5 Hz, 1H), 1.62 (s, 6H).

Synthesis of2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-13-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

A mixture of 10.7 g (25.3 mmol) of13-bromo-10,10-dimethyl-10H-indeno[2,1-b]triphenylene, 7.7 g (30.3 mmol)of bis(pinacolato)diboron, 0.3 g (0.26 mmol) of Pd(PPh₃)₄, 7.4 g (75.4mmol) of potassium acetate, and 500 ml 1,4-dioxane was degassed andplaced under nitrogen, and then heated at 90° C. for 16 h. Afterfinishing the reaction, The mixture was allowed to cool to roomtemperature. The organic phase separated and washed with ethyl acetateand water. After drying over magnesium sulfate, the solvent was removedin vacuum. The residue was purified by column chromatography on silicato give product (9.5 g, 20.2 mmol, 80%) as a light-yellow solid; 1H NMR(CDCl₃, 500 MHz): chemical shift (ppm) 8.93 (s, 1H), 8.77˜8.71 (m, 2H),8.67˜8.65 (m, 3H), 7.88 (d, J=1.5 Hz, 1H), 7.71˜7.64 (m, 4H), 7.29 (dd,J₁=8.5 Hz, J₂=1.5 Hz, 1H), 7.42 (d, J=8.5 Hz, 1H), 1.62 (s, 6H), 1.42(s, 12H).

Synthesis of 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-13-yl)pyridine

A mixture of 9.5 g (20.2 mmol) of 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-13-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 3.3 g(21 mmol) of 2-bromopyridine, 0.44 g (0.4 mmol) of tetrakis(triphenylphosphine)palladium, 30 ml of 2M Na₂CO₃, 40 ml of EtOH and 80 ml toluenewas degassed and placed under nitrogen, and then heated at 90° C.overnight. After finishing the reaction, the mixture was allowed to coolto room temperature. The solution was extracted with 250 ml of ethylacetate and 1000 ml of water. The organic layer was dried with anhydrousmagnesium sulfate and the solvent was evaporated under reduced pressure.The residue was purified by column chromatography on silica (Hx˜EA) togive product 6.0 g (88%).

Synthesis of dichloro-bridged dimer

A mixture of 7.35 g (20 mmol) of iridium (III) chloride, 13 g (85 mmol)of 2-phenylpyridine, 120 ml of 2-methoxyethanol and 30 ml of distilledwater, was placed under nitrogen, and then heated reflux overnight.After finishing the reaction, the mixture was allowed to cool to roomtemperature. The yellow precipitate formed was vacuum filtered andwashed with ethanol and hexanes. The dichloro-bridged dimer was dried ina vacuum oven to give 10 g. The product was not purified any further butused directly in the next step.

Synthesis of iridium triflate precursor

A mixture of 9.6 g of dichloro-bridged dimer, 4.6 g (17.5 mmol) ofsilver triflate, 300 ml of dichloromethane and 5 ml of methanol, wasplaced under nitrogen, and then stirred overnight. After finishing thereaction, the silver chloride was filtered off. The solvent wasevaporated. 10 g of product was obtained. The product was not purifiedany further but used directly in the next step.

Synthesis of EX2

A mixture of 9 g (11.3 mmol) of iridium triflate precursor, 9.7 g (23mmol) of 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-13-yl) pyridine,120 ml of EtOH and 30 ml of MeOH, was placed under nitrogen, and thenheated reflux overnight. After finishing the reaction, the mixture wasallowed to cool to room temperature. The yellow precipitate formed wasvacuum filtered and washed with ethanol and hexanes, the product waspurified by vacuum sublimation to give 4.3 g of yellow product. 1H NMR(CDCl₃, 500 MHz): chemical shift (ppm) 9.27 (s, 1H), 8.98˜8.97 (d, 1H),8.89˜8.88 (d, 1H), 8.81˜8.77 (m, 3H), 8.63 (s, 1H), 8.38˜8.36 (d, 1H),8.17˜7.15 (m, 2H), 7.94˜7.90 (m, 2H), 7.83˜7.50 (m, 11H), 7.19˜7.14 (m,2H), 6.90˜6.65 (m, 7H), 1.40 (s, 3H), 1.22 (s, 3H).

Example 2 Synthesis of EX12 Synthesis of2-(biphenyl-2-yl)-7-bromo-9,9-dimethyl-9H-fluorene

A mixture of 35.2 g (100 mmol) of 2,7-dibromo-9,9-dimethyl-9H-fluorene,21.8 g (110 mmol) of biphenyl-2-ylboronic acid, 2.31 g (2 mmol) ofPd(PPh₃)₄, 75 ml of 2M Na₂CO₃, 150 ml of EtOH and 300 ml toluene wasdegassed and placed under nitrogen, and then heated at 100° C. for 12 h.After finishing the reaction, the mixture was allowed to cool to roomtemperature. The organic layer was extracted with ethyl acetate andwater, dried with anhydrous magnesium sulfate, the solvent was removedand the residue was purified by column chromatography on silica to giveproduct (26.8 g, 63.0 mmol, 63%) as a white solid.

Synthesis of 12-bromo-10,10-dimethyl-10H-indeno[2,1-b] triphenylene

In a 3000 ml three-necked flask that had been degassed and filled withnitrogen, 26.8 g (60 mmol) of2-(biphenyl-2-yl)-7-bromo-9,9-dimethyl-9H-fluorene was dissolved inanhydrous dichloromethane (1500 ml), 97.5 g (600 mmol) Iron (III)chloride was then added, and the mixture was stirred one hour. Methanol500 ml were added to the mixture and the organic layer was separated andthe solvent removed in vacuo. The residue was purified by columnchromatography on silica (hexane-dichloromethane) afforded a white solid(10.7 g, 25.3 mmol, 40%). 1H NMR (CDCl3, 400 MHz): chemical shift (ppm)8.95 (s, 1H), 8.79˜8.74 (m, 2H), 8.69˜8.68 (m, 3H), 7.84 (d, J=8.0 Hz,1H), 7.72˜7.65 (m, 5H), 7.57 (d, J=8.0 Hz, 1H), 1.66 (s, 6H).

Synthesis of 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

A mixture of 10.7 g (25.3 mmol) of12-bromo-10,10-dimethyl-10H-indeno-[1,2-b]triphenylene, 7.7 g (30.3mmol) of bis(pinacolato)diboron, 0.3 g (0.26 mmol) of Pd(PPh₃)₄, 7.4 g(75.4 mmol) of potassium acetate, and 300 ml 1,4-dioxane was degassedand placed under nitrogen, and then heated at 90° C. for 16 h. Afterfinishing the reaction, the mixture was allowed to cool to roomtemperature. The organic phase separated and washed with ethyl acetateand water. After drying over magnesium sulfate, the solvent was removedin vacuo. The residue was purified by column chromatography on silica(hexane-dichloromethane) to give product (9.5 g, 20.2 mmol, 80%) as alight-yellow solid; 1H NMR (CDCl3, 400 MHz): chemical shift (ppm) 9.03(s, 1H), 8.81 (d, J=7.84 Hz, 1H), 8.77 (d, J=7.88 Hz, 1H), 8.70˜8.67 (m,3H), 8.02˜7.93 (m, 3H), 7.71˜7.67 (m, 4H), 1.69 (s, 6H), 1.42 (s, 12H)

Synthesis of2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)pyridine

A mixture of 9.5 g (20.2 mmol) of 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 3.3 g(21 mmol) of 2-bromopyridine, 0.44 g (0.4 mmol) of tetrakis(triphenylphosphine)palladium, 30 ml of 2M Na₂CO₃, 40 ml of EtOH and 80 ml toluenewas degassed and placed under nitrogen, and then heated at 90° C.overnight. After finishing the reaction, the mixture was allowed to coolto room temperature. The solution was extracted with 250 ml of ethylacetate and 1000 ml of water. The organic layer was dried with anhydrousmagnesium sulfate and the solvent was evaporated under reduced pressure.The residue was purified by column chromatography on silica (Hx-EA) togive product 6.9 g (78%).

Synthesis of EX12

2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)pyridine instead of2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-13-yl)pyridine, exceptfor using the same method as in synthesis example 1, the desiredcompound of EX12 (2.7 g, yield=41%) was obtained.

Example 3 Synthesis of EX33 Synthesis of2-(10,10-dimethyl-10H-indeno[2,1-b] triphenylen-12-yl)quinoline

A mixture of 9.5 g (20.2 mmol) of 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 4.4 g(21 mmol) of 2-bromoquinoline, 0.44 g (0.4 mmol) of tetrakis(triphenylphosphine)palladium, 30 ml of 2M Na₂CO₃, 40 ml of EtOH and 80 ml toluenewas degassed and placed under nitrogen, and then heated at 90° C.overnight. After finishing the reaction, the mixture was allowed to coolto room temperature. The solution was extracted with 250 ml of ethylacetate and 1000 ml of water. The organic layer was dried with anhydrousmagnesium sulfate and the solvent was evaporated under reduced pressure.The residue was purified by column chromatography on silica (Hx-EA) togive product 6.8 g (71%).

Synthesis of dichloro-bridged dimer

A mixture of 6.8 g (14.4 mmol) of 2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)quinoline, 1.7 g (5.8 mmol) of iridium (III)chloride hydrate, 30 ml of 2-methoxyethanol and 10 ml of distilledwater, was placed under nitrogen, and then heated reflux overnight.After finishing the reaction, the mixture was allowed to cool to roomtemperature. The red precipitate formed was vacuum filtered and washedwith ethanol and hexanes. The dichloro-bridged dimer was dried in avacuum oven to give 5.0 g (62% yield). The product was not purified anyfurther but used directly in the next step.

Synthesis of EX33

A mixture of 5.0 g of dichloro-bridged dimer, 2.3 g of sodium carbonate,2.2 g of 2,4-pentanedione and 100 ml of 2-methoxyethanol, was placedunder nitrogen, and then heated reflux overnight. After finishing thereaction, the mixture was allowed to cool to room temperature, theprecipitate was vacuum filtered. The filtered product was added to 300ml of distilled water and stirred for 30 minutes. The red precipitatewas vacuum filtered, washed with additional distilled water, followed byseveral rinses with absolute ethanol followed by hexanes to give to giveproduct 1.2 g (46%), the desired product was purified by vacuumsublimation.

Example 4 Synthesis of EX72

1-Bromoisoquinoline instead of 2-bromoquinoline, except for using thesame method as in synthesis example 1, the desired compound of example 4(1.3 g, yield=36%) was obtained.

General Method of Producing Organic EL Device

ITO-coated glasses with 9˜12 ohm/square in resistance and 120˜160 nm inthickness are provided (hereinafter ITO substrate) and cleaned in anumber of cleaning steps in an ultrasonic bath (e.g. detergent,deionized water). Before vapor deposition of the organic layers, cleanedITO substrates are further treated by UV and ozone. All pre-treatmentprocesses for ITO substrate are under clean room (class 100).

These organic layers are applied onto the ITO substrate in order byvapor deposition in a high-vacuum unit (10⁻⁷ Torr), such as: resistivelyheated quartz boats. The thickness of the respective layer and the vapordeposition rate (0.1˜0.3 nm/sec) are precisely monitored or set with theaid of a quartz-crystal monitor. It is also possible, as describedabove, for individual layers to consist of more than one compound, i.e.in general a host material doped with a dopant material. This isachieved by co-vaporization from two or more sources.

Dipyrazino[2,3-f:2,3-]quinoxaline-2,3,6,7,10,11-hexacarbonitrile(HAT-CN) is used as hole injection layer in this organic EL device, andN,N-Bis (naphthalene-1-yl)-N,N-bis(phenyl)-benzidine (NPB) is mostwidely used as the hole transporting layer,N-(biphenyl-4-yl)-9,9-dimethyl-N-(4′-phenylbiphenyl-4-yl)-9H-fluoren-2-amine(EB2) is used as electron blocking layer, and the chemical structureshown below:

In the present invention the phosphorescent emitting host used as thefollowing formulas:

wherein X is a divalent bridge selected from the atom or groupconsisting from O, S, C(R₈)₂, N(R₉) and Si(R₁₀)₂, m represents aninteger of 0 to 4, n represents an integer of 0 to 8, R₁ to R₄ and R₈ toR₁₀ are independently selected from the group consisting of a hydrogenatom, a halide, a substituted or unsubstituted alkyl group having 1 to20 carbon atoms, a substituted or unsubstituted aryl group having 6 to30 carbon atoms and a substituted or unsubstituted heteroaryl grouphaving 3 to 30 carbon atoms; wherein the preferably phosphorescent lightemitting host is selected from the group consisting of:

Organic iridium complexes are widely used as phosphorescent dopant forlight emitting layer, Ir(ppy)₃, Ir(piq)₂(acac) and Ir(2-phq)₂(acac) arewidely used for phosphorescent dopant of light emitting layer forcomparable materials in the present invention.

HB3 (see the following chemical structure) is used as hole blockingmaterial (HBM) and2-(10,10-dimethyl-10H-indeno[2,1-b]triphenylen-12-yl)-4,6-diphenyl-1,3,5-triazine(ET2) is used as electron transporting material to co-deposit with8-hydroxyquinolato-lithium (LiQ) in organic EL device. The prior art ofother OLED materials for producing standard organic EL device controland comparable material in this invention shown its chemical structureas follows:

A typical organic EL device consists of low work function metals, suchas Al, Mg, Ca, Li and K, as the cathode by thermal evaporation, and thelow work function metals can help electrons injecting the electrontransporting layer from cathode. In addition, for reducing the electroninjection barrier and improving the organic EL device performance, athin-film electron injecting layer is introduced between the cathode andthe electron transporting layer. Conventional materials of electroninjecting layer are metal halide or metal oxide with low work function,such as: LiF, LiQ, MgO, or Li₂O. On the other hand, after the organic ELdevice fabrication, EL spectra and CIE coordination are measured byusing a PR650 spectra scan spectrometer. Furthermore, thecurrent/voltage, luminescence/voltage and yield/voltage characteristicsare taken with a Keithley 2400 programmable voltage-current source. Theabove-mentioned apparatuses are operated at room temperature (about 25°C.) and under atmospheric pressure.

Example 5

Using a procedure analogous to the above mentioned general method,phosphorescent emitting organic EL device having the following devicestructure was produced (See FIG. 1). Device: ITO/HAT-CN (20 nm)/NPB (110nm)/EB2 (5 nm)/H1 to H6 doped 15% phosphorescent emitting dopant (30nm)/HB3 (10 nm)/ET2 doped 40% LiQ (35 nm)/LiQ (1 nm)/Al (160 nm). TheI-V-B (at 1000 nits) and half-life time of phosphorescent emittingorganic EL device testing report as Table 1. The half-life time isdefined that the initial luminance of 1000 cd/m² has dropped to half.

TABLE 1 Half-life Emitting Emitting Voltage Efficiency time host dopant(V) (cd/A) Color (hour) H1 EX2 3.5 45 green 1280 H2 Ir(ppy)₃ 3.8 36green 850 H2 EX2 3.5 48 green 1350 H3 EX12 3.6 40 green 1050 H4 EX12 3.828 green 1100 H5 EX2 4.0 21 green 1200 H6 Ir(ppy)₃ 3.5 22 green 960 H6EX12 3.5 18 green 1300 H2 + H6 EX2 4.2 56 green 1280 H2 EX33 4.0 14 Red650 H2 + H6 EX33 4.5 17 Red 700 H2 + H6 Ir(piq)₂(acac) 4.8 15 Red 310 H3EX72 3.9 16 orange 800 H3 + H6 EX72 4.2 28 orange 850 H3 + H6Ir(2-phq)₂(acac) 4.5 18 orange 430

In the above preferred embodiments for phosphorescent organic EL devicetest report (see Table 1), we show that the indenotriphenylene-basediridium complexes with a general formula (1) used as light emittingdopant of emitting layer for organic EL device in the present inventiondisplay good performance than the prior art of organic EL materials.More specifically, the organic EL device in the present invention usethe indenotriphenylene-based iridium complexes with a general formula(1) as light emitting dopant material to collocate with emitting hostmaterial H1 to H6 shown lower power consumption, longer half-life timeand higher efficiency.

To sum up, the present invention discloses an thindenotriphenylene-based iridium complexes which can be used as light emittingdopant of emitting layer for organic EL device are disclosed. Thementioned the indenotriphenylene-based iridium complexes represented bythe following formula (1):

wherein A ring represents an imidazole, a pyridine, a quinoline and anisoquinoline, X₁-X₂ represents a bidentate ligand, m represents aninteger of 0 to 2, n represents an integer of 0 to 8, R₁ to R₄ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.

Obvious many modifications and variations are possible in light of theabove teachings. It is therefore to be understood that within the scopeof the appended claims the present invention can be practiced otherwisethan as specifically described herein. Although specific embodimentshave been illustrated and described herein, it is obvious to thoseskilled in the art that many modifications of the present invention maybe made without departing from what is intended to be limited solely bythe appended claims.

1. An indenotriphenylene-based iridium complexes represented by thefollowing formula (1):

wherein A ring represents an imidazole, a pyridine, a quinoline and anisoquinoline, X₁-X₂ represents a bidentate ligand, m represents aninteger of 0 to 2, n represents an integer of 0 to 8, R₁ to R₄ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.
 2. The indenotriphenylene-based iridium complexesaccording to claim 1, X₁-X₂ represents the following formulas:

wherein X is a divalent bridge selected from the atom or groupconsisting from O, S, C(R₈)₂, N(R₉) and Si(R₁₀)₂, R₅ to R₁₀ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.
 3. The indenotriphenylene-based iridium complexesaccording to claim 1, wherein the indenotriphenylene-based iridiumcomplexes formula (1) is represented by the following formula (2) toformula (31):

wherein X₁-X₂ represents a bidentate ligand, m represents an integer of0 to 2, n represents an integer of 0 to 8, R₁ to R₄ are independentlyselected from the group consisting of a hydrogen atom, a halide, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 30 carbon atoms anda substituted or unsubstituted heteroaryl group having 3 to 30 carbonatoms.
 4. The indenotriphenylene-based iridium complexes according toclaim 3, X₁-X₂ represents the following formulas:

wherein X is a divalent bridge selected from the atom or groupconsisting from O, S, C(R₈)₂, N(R₉) and Si(R₁₀)₂, R₅ to R₁₀ areindependently selected from the group consisting of a hydrogen atom, ahalide, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted aryl group having 6 to 30 carbonatoms and a substituted or unsubstituted heteroaryl group having 3 to 30carbon atoms.
 5. A organic electroluminescent device comprising a pairof electrodes consisting of a cathode and an anode, and between thepairs of electrodes comprising at least a light emitting layer, one ormore layers of organic thin film layer, wherein at least one layer ofthe organic thin film layer or light emitting layer comprising theindenotriphenylene-based iridium complexes with a general formula (1)according to claim
 1. 6. The organic electroluminescent device accordingto claim 5, wherein the light emitting layer comprising an emittingdopant of the indenotriphenylene-based iridium complexes with a generalformula (1).
 7. The organic electroluminescent device according to claim5, wherein the light emitting layer comprising two or three types ofemitting dopant of the indenotriphenylene-based iridium complexes with ageneral formula (1).
 8. The organic electroluminescent device accordingto claim 5, wherein the light emitting layer comprising an emitting hostwith the following formulas:

wherein X is a divalent bridge selected from the atom or groupconsisting from O, S, C(R₈)₂, N(R₉) and Si(R₁₀)₂, m represents aninteger of 0 to 4, n represents an integer of 0 to 8, R₁ to R₄ and R₈ toR₁₀ are independently selected from the group consisting of a hydrogenatom, a halide, a substituted or unsubstituted alkyl group having 1 to20 carbon atoms, a substituted or unsubstituted aryl group having 6 to30 carbon atoms and a substituted or unsubstituted heteroaryl grouphaving 3 to 30 carbon atoms.
 9. The organic electroluminescent deviceaccording to claim 5, wherein the light emitting layer comprising two orthree types of emitting host with the following formulas:

wherein X is a divalent bridge selected from the atom or groupconsisting from O, S, C(R₈)₂, N(R₉) and Si(R₁₀)₂, m represents aninteger of 0 to 4, n represents an integer of 0 to 8, R₁ to R₄ and R₈ toR₁₀ are independently selected from the group consisting of a hydrogenatom, a halide, a substituted or unsubstituted alkyl group having 1 to20 carbon atoms, a substituted or unsubstituted aryl group having 6 to30 carbon atoms and a substituted or unsubstituted heteroaryl grouphaving 3 to 30 carbon atoms.
 10. The organic electroluminescent deviceaccording to claim 8, wherein the light emitting host is selected fromthe group consisting of:


11. The organic electroluminescent device according to claim 9, whereinthe light emitting host are selected from the group consisting of:


11. The organic electroluminescent device according to claim 5, whereinthe light emitting layer emits phosphorescent red, blue, green andyellow lights.
 12. The organic electroluminescent device according toclaim 5, wherein the device is an organic light emitting device.
 13. Theorganic electroluminescent device according to claim 5, wherein thedevice is a lighting panel.